Throws TypeError if multiple visibility keywords are given to member builder

lib/member_builder.js

@@ -39,19 +39,46 @@
  */
 exports.buildProp = function( members, meta, name, value, keywords )
 {
+    getMemberVisibility( members, keywords )[ name ] = value;
+};
+
+
+/**
+ * Returns member prototype to use for the requested visibility
+ *
+ * @param  {{public: Object, protected: Object, private: Object}} members
+ *
+ * @param  {Object.<string,boolean>}  keywords  parsed keywords
+ *
+ * @return  {Object}  reference to visibility of members argument to use
+ */
+function getMemberVisibility( members, keywords )
+{
+    var viserr = function()
+    {
+        throw TypeError(
+            "Only one of public, protected or private may be used"
+        );
+    }
+
+    // there's cleaner ways of doing this, but consider it loop unrolling for
+    // performance
     if ( keywords[ 'private' ] )
     {
-        members[ 'private' ][ name ] = value;
+        ( keywords[ 'public' ] || keywords[ 'protected' ] ) && viserr();
+        return members[ 'private' ];
     }
     else if ( keywords[ 'protected' ] )
     {
-        members[ 'protected' ][ name ] = value;
+        ( keywords[ 'public' ] || keywords[ 'private' ] ) && viserr();
+        return members[ 'protected' ];
     }
     else
     {
         // public keyword is the default, so explicitly specifying it is only
         // for clarity
-        members[ 'public' ][ name ] = value;
+        ( keywords[ 'private' ] || keywords[ 'protected' ] ) && viserr();
+        return members[ 'public' ];
     }
-};
+}
 

test/test-member_builder-prop.js

@@ -94,3 +94,31 @@ function buildPropQuick( keywords )
     );
 } )();
 
+
+( function testThrowsTypeErrorIfMultipleVisibilityKeywordsAreGiven()
+{
+    assert.throws( function()
+    {
+        buildPropQuick( {
+            'public':    true,
+            'protected': true,
+        } );
+    }, TypeError, "Cannot specify multiple visibility keywords (0)" );
+
+    assert.throws( function()
+    {
+        buildPropQuick( {
+            'public':  true,
+            'private': true,
+        } );
+    }, TypeError, "Cannot specify multiple visibility keywords (1)" );
+
+    assert.throws( function()
+    {
+        buildPropQuick( {
+            'protected': true,
+            'private':   true,
+        } );
+    }, TypeError, "Cannot specify multiple visibility keywords (2)" );
+} )();
+